Automatic telephone system.



S. B WILLIAMS, Jn. AUTOMATIC TELEPHONESYSTEWI.

APPLICATION FILED IAN. 3|. ms.

LMWWH; V Pawmd Nov. 2?, 191?.

4' SHEETS-SHEET I /h van for. Jdmz/e/ 6. MW/a/w fir S. B WILLIAMS, .ln.AUTOMATIC TELEPHONE SYSTEM. APPLICATION men me. a1. 1916.

Patented Nov. 27, 1917.

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Saue/ B. Wwms J1 4 SHEETS-SHEET 3.

'htented Nov. 27, 191?.

s. B. WILLIAMS, 1n.

muwmmlc TELEPHONE 'svsrsm. APPLICATION FILED IAN. 3h I916.

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I mime 1 Emm erera fiwrr its Airtime iif W ILL I AMS, in, or seamen. newease.

I nssrenonf to, wnslrnnii ELEC- mnrccolvrranr, incoarona'rnngor Newman,n. a conrona'rlonjornnw YORK. 1

Beitknown that 1,;SAMUELB. YVILLIaMs,

:Jr, a citizen of the United- States, residing at Brooklyn, in thecountyiof; Kings and *StatebfNew York, have invented certain new anduseful Improvementsin Automatic Telephone: Systems,- of l which thefollowing is a; full, clear,- concise, and exactv descripition. a

; 'Thiswinvention -relatesoto' automatic tele' phon'esystenis,anduparticularly to systems i of the type in iwhich'ftheractofinitiating a call causestheYfindingpswitch mechanism to seek andtestablish connection with the terminals of the calling line. Theinvention has particularly to do with a system of this sort in which theswitchmechanism first seilects a{ group in which' the calling line islocated, and then findsthe partlcular l1ne 1n :that group that iscalling.

"One ofthe objects of the inventionis to prevent a single linefinding'mechanisin from searching for and establishing connection.witlrtwoilines in different groups at the salnetime, when calls indifferent groups are initiated simultaneously, or practically si-:multaneously. In the particular embodimentlin which the invention; isillustrated,

gthe findin switch is of the 'inulti )le brush type, that is, ofthetypein which'the 1novable element is provided with a plurality ofbrushes,.-one for each of the groups of lines served by the switch.Thebrushes are normally held in position not to engage their respectivestationary terminals, and one or anotherbrush, or set of brushes, istripped and made operative;dependingxupon: the group in which thelinethat-is to be engaged is located. 1 a

i In automatic: telephone systems of the type to which this inventionrelates, it is the practice to provide a plurality of extension circuitsterminating upon line finder switches allrof which have access to thesame group or groups of lines, so that the calling line In'ay have itsconnection extended through the medium of any one of the finder switchesthat is not in use at the time One of the objects of this invention isto provide an organization ,in which the initiation of a call causesone, and only one of the plurality of idle finder switches to becomeactive to extendthe connection of the calling line. iYhen a subscribercalls, one a th fi d r susta ns ans- 1 i n use is j AUTOMATIC rstnrnonn'sirsrn-ivr.

Patented "Nov. 27,1917. 75,329. V

made active through the medium of astart ing circuit cjornrnonto thefinderswitches and to thelinesthat they: serve, and makes connectionwith the calling line. ,lnits movement the finder switch that isselectedplaces ,another finder switch in readiness torespond ,to-the nexticallthat is initiated. The cal} ,ing condition of the line, which results inthe starting of the finder switch persists until the findercalling'zline, which may be some timesubsequent-to the time when thenext finder switch in order hasbee placed in operative relationwith thestarting circuit. To prevent the continuation of thiscalling conditionof the line from causing the starting of the next finder switch inorder, the system is so organized thatthe calling line is de- -privedt ol COIltI'OluOVBl the starting circuit from the time the next finderswitch has been placed in readiness until, the started switch findsandalters the starting condition of the calling line. i Another object ofthe invention is to prevent the lines of any one group, where more thanonegroup of lines has access to the finder circuit mechanism, fromhaving un- Jdue preference in their control over the finder circuits,and thus tending to monopolize their use. In theembodimentof theinvention here illustrated, the lines sei'ived in common ;by severalfinder switches are di- "vi'ded into groups, these groupsbeing sorelated to the starting and group selecting circuits of the finderswitches that only one group at a time has access to them. Thearrangement is such, however, that the linesof other groups have accessto the finder switch controlling circuits as soon as the finderswitchfirstselected is started and another finder switch is placed inreadiness;

whileithe lines in the groupiin which the callingline is located,- arecut off from access to the startinglcircuit fora somewhat longerinterval, an interval long enough to switch has connected with} the isinitiated on one of the lines seryedby a. group offindj'er switches, a'tripping device will bejactu'ated'which is arranged to release any ofthe brushes of said switches which have access to the calling lineterminals and which are in normal position. Heretofore,

in.- systems of this type v atripping device haslo'eenemployed for eachswitch and it has been necessary to operate this device during apreliminary selecting movement of jtheswitch in order to select andrender operative'the desired set of brushes. Inthe present system thetripping devices arecommon to all the switches of a group, one trippingdevice being provided for all the brush setshavingfaccess to the samesection of the panel banln The particulartrippingdevice for releasingthedesired set ofbrushes "is v V I operated prior to the actuation of theswlteh.

Thisallows selection to take place rapidly without the 'relati'velylongpreliminary brush-selecting movement required by prev ,vious systemsof'this type.

A preferred embodiment of the invention,

'in which the above-mentioned and other novel features are realized, isdisclosed in the accompanying drawings, in which Figure 'l is a sideelevation with parts broken away of a'switch having a common trip rod,and of a type suitable for employment incon -nection with thisinvention; Fig. 2 is a perspective view of a portion of, the trip rodtogether with the trip and restoring levers off'a pair of brushcontrolling devices; and

Figs. 3, 4 and 5, taken together, with Fig. 3 at the left and Fig. 5 atthe right of Fig. 1,

show the circuit organization; As the switch shown in this system, withthe exception of the common trip feature employedin this invention, maybe the same and oppositely rotating power members.

To move the 'shaftup, the extension fz is brought into engagement withthe power nilember 3 by; means} of the idler pulley 4 operated by theclutch magnet 5; and to niove the shaft down, the extension2 is broughtinto engagement with the power member 3 by means of the idler pulley 4operated by the clutch magnet 45.

Secured to the shaft 1 is a plurality of sets" 6, 6" of brushes. Thesesets are usually ten in number and corresponding brushes thereof aremultiplyconn'ected. Each set 6, 6" of the brushes is adaptedto traverseasection 7', 7 ofja panelbank of'stationary contacts. The brushesof'ea'ehset 6,56 are normally maintained in inoperative "position bybeing' spaced apart or separated bymeanapfa brush controlling device .8,10?.

catedbctween the innermost brushes of the set. This controlling device 8is adapted .to be rotated to release the brushes and allow them toapproacheachq'other so as to engage the contacts in the panelzbank. rSecured to each controlling device' 8, are a trip lever "9- and arestoring "lever. 10; Extending transversely to t stiest of agroup ofswitches are 1 a' plurality of rotaitably mounted trip rods 1 1', one;for "each. set of brushes on any one of the switches. These trip rods.11 extend parallel to the 'plane o'f the shafts l-of the switches ofthegi'oup, and are normally positioned iju'stbelowxthe restoring levers10 of the brush sets when they are in their normal positi'ons.- Rota-'tahlysecuredto the rodsf'll are a series of yoke or U-shaped members,12, one-being provided 1 for, V and adapted to' brought intooperativerelation with each .of the trip levers 9 adjacent thereto (seeFig. 2). Springs 13, each having one'fendsecured to the rod 11 and theother end .to one of the yokes, tend'to force the yokes in a clockwisedirection,.which movement, however, is limitedby means of the stops 14fixed to therod.

Secured to each of the rods 11,-near one end thereofyis a crank member15 which is secured to the armature 16 of the tripima'gnetfl'? by meansof a link 18. -Upon' the energiz'ation of the magnet 17 and the atrod 11will be causedto rotate. in a clockwise direction, as viewed. in Fig. QLThis will place the yokes 12 thereofabove or in operative relation tothe trip levers 9 of all the switches of the group which are then innormal position; If, nowpone of the switches be caused "to move upwardlythe traction of its armature 16, a corresponding V brush controllingclevicewill.berotated so as to 1 release the set of brushesporrespondingto the operated trip rod.

Referring now to th eircuit=organization illustrated in Figs. 3,14: and5, this is shownto consist of two subscribers lines extending, fromtheir respective stations A. and B toymultiplestationarycontacttern'iinals on a panel type switch which coinprises aplurality of linelinders jofwhich' only two s and S', are shown Thetwoswitches S and S"'form the-. line-finding terminals of" two i connectingor trunk circuits F and F' The) telephone line from the station A isrepresented as extending to multiple terminals in one group,[=and thetelephone line frem'station as extending to multiple terminals inanother'group of the line terminal'groups served by the two mmgwi finderswitches s ands". '7 The iapparatus common to. the group of {lines tliatincludes the line extending tostation 'A,'*-*is reprecommon to the gro po'fline's that inchildes the line ex tending to 1 station F B srepresentedatG iiiFig. 3. The group apparatus-oii sti'll anothergrouplis slre'wn at Gr in Fig. 3.

the circuit =at 'the central oil" Atthe bottom ofFig. 3 there is "shownat C ce'rtain apparatus common to allqofgthe groups of li-nes, and whichserves to distribute or allot thecalls to idle fincler switches.

Thegroup apparatus ofeach figroup of lines is controlled through theinedi rmiioi' apparatus individual to @3011 of the: Various l1nes xofthe corresponding group? group apparatus, in operat ng,

the mediumof the apparatus acts-'tli'rough common to the groups tostartan idle finder switch 'that has been preselected by' thecjon iinoirap 'paratus. It also acts-to trip the set of brushes correspondingto-the group iiiWy'hich the calling line is located; and to -prevent,

the tripping of another gset'bffbrushes "through tliei'medium ofthe goup *ap'pa ra tus of another group of lines. As indicated at -theright-h-and side of =Fig. 5,-eacli$ofthe finder circuits is providedwiunmeans for 30 extending the circuit ofthe. calling line to othercircuits through tvhicli the callingline may be connected with theWanted line."

' =Itis Fthou'ghtth'at a? descriptionbfthe manner in Which thesyst em'operates will make "clear the organization and inter relation oi theelements ofwvhich the system "COIlSlSlDS.

Let" it bea'ssuined that 'the "s'ubscriber at station A desiresconnection l with some other subscriber,"-- aiidfl takes his telephonefrom its hook. The closing of'the circuit atstation A energizes the.subscribers *line relay 61 and also the relayf Ycommon to the "group,"over a"circuit that-extends from battery through the relays 50 and "51inseries, andthenceto=station A oyer one side ofthe' line and back togrio uiid ati the central oflice over the etlier' 'si'de ef the line;ice passing tl'iifough normally closed contacts of the cutof theassociated group' G, as well as the corresponding trip magnet 17; areall connected in parallel frombattery to the i rent contact of the grouprelay350,"*the armature of'this '55 relay being connected witlrjgroundat 86 'thro'ugh normally closed contacts of the relays 53, 53, *and"'53"1of the respective groups (ah-G7, and G (lonsequently' when the relay50is energized by- 'the: taking-of the telephone at station A, it closesan ini- "tial energizing circuit for the groupyrelays 53 and 154s andthe t rip' magnet 17. The

closure of this energizing circuit" by the relay 50' is subject; 1however, 1 to "the not operatedcondition of "the relay 55 f *theassociatedgrou and the relays 5 3" and- 53 et-the other groups G and Gthiough *Whiclr-the energizing circuits-extends to ground at 86.

- The conditions under ivhich the closure of the i'nitral energizingcircuit may be pre- :v ented by the "opera-ted -(3OI1Cllt1OI1 of anyonecii these relays, Will hereinafter be described: ihor; the present itWill be assumed =that these relays are inert; and "that the relays 53'-and 54 of roup- G: andtheassociated tripmagnet 17 are operated by relay50 iniclosing its contacts. l Relay in open atingcloses 111 its uppercontacts an energizmg path for itself, relay 53V and} trip magnet "17,which path 1 extends directly to ground by Way oi' restingconta'cts ofthe *rel ay56 common to the group; Trip Inagnet 17 in operatingrotatesthe' trip'rod 11.

to "bring all of the yokes 12 into position to release Ethecorresponding group brushes of j i hicliever finder 7 switch is started.Rela inoperating interrupts in its right-hand resting contacts 63 and64," the path to ground '86 over which the initial energiza tionof= the"group relaysand trip magnets "tur'e ap lies'ground to a conductor 57common to all of thegroups. 1

The application of ground to the conductor 57 causes the startingof anidle finder "switch, the particnla 1' one started being determined bytheposition of the allotter switch which; with its controlling'relays 106'and107, is illustrated at C in Fig. 3. "The allotter-in "thepresentinstance consists of anmrdinary sequence switch with its associated camsor-commutating disks 101,

102, 103, lOifand Thesequence switch is shown merely diagrammaticallyand may be ot the type disclosed in Patent 1,127,808 issued February 91915, to Reynolds and Baldwin, Contact=101 is-openwhen the sequence;switch, islinl the positiens indicated 202 (1) and motor magnet ofsequence switch 200 of the finder ci'rcuitFJ Thisscquence switch 200 andthe sequeiice switch "200 of finder circuit Finay also be ofthe typedis-'closed in the p'atent 'to Reynoldsand Baldtwin heretofore mentioned;the numerals a'pplied to the contacts 201 and 201' respectivelyfof thetwoswitches indicating positicns inWhich-these contacts are epened,

'While thenumerals-applicdto the other contacts of the two switchesindicate thepositions in which the associated contacts are closed. Theclosure motor magnet of sequence switch 200 and causes that switchtomove out of position 1 andinto position 2. In position-2 sequenceSWltCll 200 closesatcontact 2112a circuit-that energizes the up-drivemagnet 5 ;.of the associated finder switch S, this circuit 0 eXtendingfrom battery through magnet 5 and byswayof conductor'31 to: sequencegrouptri magnets is at the time-energized.

switchrcontact 211 and thence toground way; of the restingcontactsofrelay 220.

Theenergization of the up-drive magnet 5 starts the upward moyementio fthe brushes ofjfinder switchs. q a 1 An instant fatter the upward Imovement sstarts, th e tripping levers 9, of all the setsof brushes {ofi the switch, reach the position where they are adapted to beengagediandtilted by one or.;another of-the tripping yokes; 12, depending juponwhieh olf the As substation A is assumed to be calling, the

. trip magnet 17 is operated and therefore the As the brush carrying rodS' noves past the position where the set of brushes 41 of the startedtinder switch S are tripped and madeoperative.

1 of theswitch brushes istrippecl, the grounded brush 455 at thetop ofthe rod'comes into engagement with the commutator segment t, thusgrounding the conductor 46 which extends to sequence switch con'tact205; and as the sequence sw tch is at the fame in posit on 2,

the circuit is completed by way of contact .1205, (2), conductor 60 andallotter sequence 7 switch. contact 105 to the right-hand restingcontacts of grelayi l06 ig.j3),and thence by way of the winding of relay10,6 and sequence switch contact 102 (1 to bat- Ztery- Thiscauses therelay 106 to break this circuit, and apply;. ground directly by way .ofits right-hand, armature, this ground maintaining, the relay .106energized, until its 011'011113 is lOI'OkeILlIl sequence switch con-'tact 102 by the moving of allotter sequence switch 100 out of position 1in which it has been. resting, t

. It w'llbe remembered that when station called, relay 54: ofgroup -G'in operating applied agroundby way cf its upperarmature and the restingcontactsofgroup relay l56i 'tohold relays 53 and 5e and trip magnet 17Qenergized independently of the initial energizing path byway of theseries. con- ,tactsof relays 53 toground86'. ,When relay fitoperated, itconnected in its lower contacts the lower winding of relay 55 withconductor 61. The initialenergiziationg of relay ,55 is thereforedependent upon the application of ground to conductor 61, and

v of the circuit traced above by .wayof conductors 57 and 5S energizesthe 'ELftGI. I V .l Under the condit ons assumed, relays 54;. .and 550:6group Gare now locked up. awaitthis is efiected when commutator segmenttionQto energize relay- ;106Q0f; the. common group'jG, in the-manneralready'described. Thus when the grounding of, commutator segment 4 4marks the jc'ompletion of; the 7 group selecting operation, the Yfenergization of relay 55f of;gr o uplG is efiected initially by wayofthe groundyatcommutatorsegme nt 14, then bywayofthe groundl applied.in .thef -right-hand armature "of, relayv 106 when that relayoperatesand 'finallyrlby the ;closure,;of;- alocking circuit by waypofits upper winding, itsupperalternate contacts, theupper; closed contactsof relay 5i and the resting contactsgof ,relayg56f .to ground.

Thereafter, the; maintained energization of relays 5 4 and 55 is subjectto the control of relay 56 relays 54:. and 55, becoming :inertwhenrelay56 is energized; r

1;} Relay 55- in operating breaks thei to trip magnet. 1'1 ghad theretofore been held operated, and pernntsboth to become inert. Furthermore,as long as relay, -55f1j8mE1-1I1S locked up, it holds openthe'circuit1between the 1 contacts otthe groupjrelay .505 and theenergizing-windings of the relay-53 andthe trip magnet 17, so that aslong as. "relay 55.

remains operated, neither the; calling; line vfrom stat on A nor any;other .line ,otthe associated group can exercise; any control over therelay .53. and the corresponding trip magnet 17.. But. when relay'53isdeener gized by the1energization of relay. 575,1 it again closesthe,inteiwgroupseries circuit in .its-right-hand resting conta'ctsfsothat the re1ays53 and tripmagnetsio'f other groups may beoperated by theinitiation-of calls in, thosegrou'ps. .The reciprocal control exercisedbythe Various groups over each other-will be particularlydeseribed-herein- 7 ing the energization of; relay ,56, thesel q? witch200,0ffin der circuit F is {in pos tion 2, and thei brushes {of finderswitch 2 corresponding with "the group iniwhich line A is located, 1'are, released-and moving up 1 overxthe terminals of-the lines'iof that.group. .In p0s1t1on 2 of sequence'switch 200, a testingclrcuit iscompleted from battery through test reljay 220, sequence switchcontact-206, (2..to. 3), conductor :47 anditest 44 of'finder switchS,,is engaged rbybrush 43 at the endofthegroup ,selectingoperabrush .36to the test-conductors 2350f the V of station A, a circuit. for test relt amwof this, relay, and consequently a when test brnsh'36 engages theterminalsof the line in, 220 f findencircuit F-is completed to ground byway of test conductor 23, front contactsjof line relay 51- and windingof group elay 56. flhecompletionof this circuit operates relays 2-20 and56.;mRelay 56in operating opens, the locking circuittof the y 7 group,relays 54L; and 55, restorin'gsthe group circuit to normal and againgiving the lines of the group control over relay and trip V magnet 17throu h the mediumofrelay 50I Relay 2201n-openit1ng opens intsbackcontactthe energizing;,clrcuit ot the up dr1ve magnet 5, thusstoppingythe upward move ment of the switch brushes, and closes in itsfront contacts an energizing c1rcu1t for the 2 motor magnet of scquenceswitch; 200, by

way otsequence switch con'tacts 202, (2), thus moving the sequenceswitch out or .po-

sition 2.

Immediately upon moving out of position2, sequence switch 20 0 closesaci'rcuit that operates-the cut-otlrelay52 ofthe line of calling stationA, Thiscircuit may winding of cut-off, relay 52 tojground. Cut-oft relay52 in operating disconnects grouprelay and linerelay 51 fromthe line ofcalling station A, andboth of these relays thereupon releastheirarmatnres,

To lnsure the opening of the group ini 7 tin]. energizingcircuit n; thecontacts oit ,re-

a My 5b 01i i is reestablished in the con tacts of relay 55, relay' ismade slow to release-as by placing a copper sleeveebout its core andapplying only a, weak retractile force to its armatures.

At tl e right in Fig; l shown the terminals ot. the finder CllfCllltS,

These terminals diagrammatically represent contacts of aswitchnig deviceor any'de sired-character, either manual or mechanical. When thecallingsline, is fOllDd,,tl1iS6- quence switch 200 moyes 0L1i3 ,0f,position 2, as abovev explained, and is carried by its governing contact201 toposition at, where it remains until the-finder circuit is joinedto the nex-t link inthe talking circuit, by the terminals E beingconnected wlth contacts, as thoseiindicated adjacent thereto.

, When this occurs, contact 223 will be closed in. any desired andobviousananner, conn i pleting a circuit frombattery through-relay 225,contact/ 207 ,(,4'),lower terminal LE and,

contact 223, to ground. Relay225; is} enela gi zed and completes acircuit from: battery through the noton magnet of sequence switch 200,contact ing the sequence switch 200 to position 5.

'llheicalling line is now GXtQIlClHt-i-O-llllfl terassociated" b traced;from battery through resistance coil; 221, sequence switch contacts 2109; test), conductor 48, brush L1, conductor 42and 5, at E and E, are,

224 (it); and front contact and armatnre of relay 225, thus;moyminalslfl by contacts-208 and-209; ln iposition at the upperandlower, contacts of se quence switch spring 210 are closed. Wljren theterminals E unite with the contactsot the-extension circuit,batteryissupplied,to T0 the third from the topico ntact of saidciicuit,-;and through the third it'rom the top terminal E to the Contact210 i, and 5),

thus insuring that the remain energized when from itscircuit atflupperContact 210, when the sequence switch moves to position The circuitcondition described aboveis that which ,exists while the subscribers aretalking. hangingup of the telephone,at station A bringsabout the'openingof ,contact223 in, any desired and obvious manner, and this in turnopens, the circuitqoi relay 225. The

relay n armature of the last,mentionedrelay in fall-i ing back, appliesground'for energizing the motor magnet-of sequence switch 200bywayofsequence switch contacts 202;( This moves thesequence switchlout ofiposition,

5 and intojposition 6. In positionifioiithe reach their normalposition,commutator seg- 95,

a calling line and its finder-switch isstarted 1,05

and passes the group ,selectingistage otzits operation, another finderswitch and circuit are placed in readiness to take thetnextcall; This isaccomplishedin the following man ner: Ashas already beentdescribed,.imme- 1,10

diately-aiter the brushes have been tripped, the moyeinent of ,the,linden switch causes the grounding of segment li ofi:the1com-I mutator,and, the, ground thus applied oper ates-relay 106-of,t he common group Cand relayv55 of the particular groupGr in which the calling ,line islocated. Relay 106 in operating closes in its leftjhand contacta circuitfor energizing theomotor magnet oi,

allotter sequence switch 100; The instantlZO sequence switch 100 starts,to; move, it, opens in its contact 102 (l) the energizing circuit, of;the relay 1,06. Thatrelay theneforefis but-momentarily operated, beingenergized by the impulse. 0 f; current from the; p assing 1 2 5 contactoi grounded brush 43, with commu tator segmentdt, and immediately upon?energizz'ition acting to startbsequence; switch 100 and thereby to breakits own energizing circuit in} contacts 102 (1;) of the sequence batteryis removed 75 At the end of the conversation the so This 100 switch:Sequence switch 100, asxa result of the momentary operation of relay106,

moves into position 2, where the energizing circuit for its motormagnet, by way of sequence 7 switch contacts 101, is again opened.Sequence'switch contacts 103,101

and 105 in each resting position, of the sequence switch extend thethree. conductors which they control to a different set of conductors58, 59 and 60, each set of conductors extending to a different findercircuit.

When the allotter sequence switch 100 stood inposition 1, the circuitscontrolled by itwere extended to finder circuit F. In

moving to position 2- upon the starting of the finder switchoffinder-circuit F, the circuitscontrolle'd by the allotterare extended byWay otswitchcon a S 104 M11105 andconductors '58, 59 and 60; to findercirquence switch 200- cuit'F. g the finder circuit F1s not in use, itssel 59' and 60 are open in their respective concircuit that is .idle.

tacts of sequence switch 200-. This" being thecase, allotter sequenceswitch 100' rests in position 2 until the initiation of the 'ne'nt. callapplies ground to conductor 57st the;

starting cir'cuit,whereupon sequence switch 200 otfinder-circuit F;ismoved into'p'osition 2, the associated finder switch- S is started,and the grounding ofcom'mutator segment 14: of finder-switch Soperatesrelay 106 and causes the allott er sequence switch 0 to be movedout of position 2 in which already described indetail."

a If the finder circuit F is in use, its sequence' sw tch is'in a postion from 3 to 18' inclusive. Now whenthe allotter sequence switch 100movesl'from position 1 toposition 2, it completes a circuit frombatterythrough lower contacts 1-02 (2 winding and-- right-hand resting contactsof relay 107.,

contacts 101(2), conductor 59 and sequence switch contact 520 1- (3 to18) to ground;

Consequently relay 107 operatestofclose, in

itslet't-hand contacts, an energizing circuit for the motor-magnet ofallotter switch' 100, and the switch is moved through position 2.- Inlike manner the allotteris'inoved through the positions correspondingwith finder circuits that arebusy, and whose sequence Assuming inthefirst place that is in position 1, and con se'qu'ently all three ofthe 'co'nductor's 58,

in amanner similar to-thatf mam calls simultaneously. Under 'thisassiimp tion relay of group G V and relay 50"" of group Gr tacts at thesame instant; As previously described, when the relay 50 operates,-ittendsfl and 5 1 and the corresponding "trip magnet 17', 1 Thiscircuit includes conductor; 6:2

are energized'and close their-c011 to close a circuitfor'the associatedrelays53 V V which extends, serially through resting contacts of therelays 53 of all the groups to. ground apse. "In likema nner relay 50-ofgroup (3 tends to close a'similarcircuit for" the associated relays53and-51 and the cor responding trip magnet 17, which circuit; alsoinclud'es conductoi"'62 that extendsasertallythrough the resting contactof the relays 53 of the difieren't groupsl Consev quently, whenany ofthe group relays 53, 53 or 53 is operated'far enough to inter-' rupt itsright-hand resting contacts, it thereby interrupts the initialenergizing circuit 7 for the relays and trip magnet of any other group..i 7' 7 "As relay"50 of group G and relay 50 of group G are assumed to beenergized and to close. their" contacts simultaneou'sly, f for aninstant each completes the i'nitialenergizing circuit of its -'associated rel ays and trip mag netvbyof co11ductor62, and relays 53 and 53both start topullupil But at the outset of the attractive movementrel'a'y 53 opens its contacts 63 andthusinterrupts the initialenergizing path of *relay 53 to ground 86 by way of conductor 62.Ascentact 6 1" of relay 53 has not opened at this stage of theoperation, the initial energizing circuit of-relay 53 by way' ofconductor 62"- is maintained, and the continued flow of can renteausesrelay 53- to bring about thefu-ll' attraction ofits armatures;Contact 61 of relay 53 is broken toward tlie'end of the-attractivemovement; but before this-[happens, the inner left hand contacts ofrelay 53 are closedjthus providing an energizing pathfor relay '53independent of its con tacts 611- As long" as relayj 53 re nains oper=ated itfhold's; the energizingpath 52101 the other" groups open finfitsI contacts 63 and 61, and therefore, Lalthough relay; 50 is heldoperated by calling subscriben-B, it is; ineffective to cause theoperation of the asso ciatecl relays 53- and 51;- andYthe correspondingtrip magnet 17; This is alsojtr'ue with respect to any relay50'thatmaybe operatedf as the result of a call 'inany othergroupi As the tripmagnet and the relays 53 anid5 1= of each group operate together o erthe samei energizing-{- circuit, "the arrangement described preventsmore than a single It'ri'p magnet beingoperated at atime and 'insureslthat only a single set of brushes on the-finder switch-will be broughtinto operative rela f tion withits associated line; terminals, Y If. it}had happened thatstationB ha'cl' called, an-inst-ant ahead- 0f station 5A,"tliena y ation of more than the 5 corresponding relay -53 would haveinterrupted as-Hby providing: their cores with copper finder switch atthe'co'mpletion of the group p the group relay to cutoff circuits on themg c rcult and. at othertimes, these relays oftgroup G, in its contacts64, the conductor 62 upon which relay 53 of group G. depends for itsoperation; and therefore the closure of the contacts of relay 50, as aresultof the calling of station A, would not be effective to-fclose anenergizing path for the associated relays 53 and 54: and thecorresponding trip magnet 17. Thus in all cases the operone trippingdevice is operating .and opening prevented; i i

To preventa tacts of'the relays 54 of the variousgroup closure of theinitial energizare preferably of type whichinakes them slow to closetheircontacts as a result of their energizationb This characteristicunay be giventhem in any well-known manner,

sheaths and giving. their armatures' or switch springs a relativelystronglretractile tend encyp To procurethe best results eration oftheisystem, the relays 54 should be relatively slow and the relays 58"relae tively quick in operating; While the relays 55, asheretoforepointed out, should be rel atively quick in operating andslow in releasing: Also it isdesirable that the allotter sequence switch 100should move} its contacts quickly upon the energization of its motormagnet. i i t a The system isv so organized that although the findercircuits are placed in readiness to respond-1 to calls rapid"succession, and in less time thanus requiredfor a started finder switchto find anchconnect with thetermt nals of a calling line,' ;thecontinuance of the calling condition of a line after a finder is startedand another placed in second finder switch, vThis is accomplished by soorganizing. the system that the impulse of current which is produced bythe started selecting operation, not only causes the al lotter to placeanother finder circuit in readiness, but also deprives the calling lineof further control over the starting circuit. In other words, as hasheretofore been described, the grounding of the commutator segment 44atthe completion of the group selecting operation of the finder switch,not only advances the allotter 100 to bring another finder circuit intooperative relation withithe group circuit, but also energizes theassociated group relay 53 and trip magnet 17fro1n control by the relay50, and to keep the relay 53 and magnet 17 disconnected from relay 50until the relay 56 is energized to release relay 55 at the finding ofthe calling line and the consequent release of relay 50. The

prematureclosing of the coni in the op magnet until the complished haveheretofore beenidescribed in detail. a y Another result accomplished bythe o1- ganization described above is that l' O'ft time aftereach grouphas hadaaccess to the starting circuit and to the control of itscorresponding group. trip 1nagnet,.so1ne other group has theprefcrencein controlling the startingcircuit and the trip magnet associated withthat group. Thus the operation of the relay 55, which releases theassociated relay 53 and tripping devicefl'? and renders themirresponsive to the control of tho nssociated relay50until after thecalling line is found, also, in the releasing of relay 53, restoresthelinitial series energizing path 52 for. the group's andrenders itpossible for any. other group to operate its group, relay 53a'nd tripvmagnet 17 and thus avail itself of the servicesofthe other finderswitcha lid circuit which the allotter has placed in readiness. Therefore if,for instance, two calls are initiated in group G 'andone call in groupsimultaneously, relay 53 and trip magnet 17 of group G will be operatedto start'and trip the brushes of the waiting finder switch, after whichgroup G will be deprived of control ,over its relay and first in orderof the. two calling lines in group Gris found. Butthe firststartedfinder switch at the conclusion of itsgroup selecting movementacts through the .allotter 100 to place another finder switch inreadiness; and .as relay of group. G; inoperatinglto' depriveuthe linesofitsasso'ciated group'of control over the associated trip magnet andthe common starting circuit, releases relay-.-' 3 to restore the controlof the other groups, thecall that is" Waiting in group G startsthesecond finder switch and operates magnet 17''. to

trip the corresponding group brushes. When theseeond started finderswitch acts through the allotter; 100 to place a third finder switch inreadiness and restore the control of the other groups over the startingand tripping circuits, and when the finding of one of the calling linesin group G releases relay 55 and again makes relay 50 effective tocontrol its associated relay 53 and trip magnet 17, then the thirdfinder switch is started to take the second of the two calls originatedin group G. Thus it is impossible for a number of calls initiatedpractically simultaneously in one group, to monopolize the services ofthe finder switches, as after each use of the starting and trippingcircuits by one group, the calls of other groups are given control overthese circuits in prefer ence to calls waiting in the same group.

What is claimed is: g

l. The combination with a plurality of lines, of a plurality of finderswitches for making connection therewith, a starting circuit adaptedwhen actuated to start one of said'finder switches, means actuatedat theofeach of said said starting c1rcu1t,and means actuated by said startedswitch for temporarily preventvented. v 1 a p '2'. The combination witha plurality of brush, anenergizing circuit for each of said: devices,means for closing-each energizing: circuit, means actuated intheclosure: of any of said energizing circuits for rendering the copiesot this patent may beobtained for five cents each,-by 'addressing'theCommissioner;otjatiitggj ing a second actuation of saidstarting'circuit-by said calling line, whereby thestart ing of twofinder switches by one call 1s prelines divided'into groups, of aplurality of finder switches for making connection therewith, a startingcircuit for said nfinder switches, linecontrolled means for each groupof lines adapted to efi'ectthe energization of said starting'circuitto-startza finder switch, and means actuated in the starting ofsaid'switch to render-the line controlled meansxof said grouptemporarily ineffective and to place another finder switch under thecontrol of said othergroups;

3. The combination with a plurality of lines divided into groups, aplurality of finder switches for making connection therewith, startingmeans for starting said. switches consecutively, a group selectin'g'de'vice common to said switches'for each group oflines, means actuated uponthe init ation of a call 'for operating said starting-means and theselecting device of. the group in which the calling line is located, andswitch-: ing mechanism controlled in the movement of the started finderswitch for rendering, said means thereafter-temporarily irresponsive :toa call inthe same group. a 4:. In a telephone system, the'combinationwith a multiple brush line finder, of: electro magnetic trippingdevices, one vfor :eaclr other Zcii'cuits inoperative, means controlledin the movement of. the line finder forkrendoling: the first mentionedcircuit *inoperative and-gsaidother circuits operative, and

means actuated in the further movement of I said 'line finder forrestoring said firstmen tioned" circuit to operativeness'. K 7

a 5. In a telephone system, the combination with telephone linesarrangedin groups,- of a .finder. switch with which said telephone linesareconnected, said switch'being adapt-- ed for group and individual lineselection, a

device associated with. each; group fof lines for controllingthe' groupselecting operationof said swltch withirfespecttothecorrespond: mg groupof lines, said device being nor-;

mally operable by the initiation ofa callin any 'lineof itsassociated-group,- inean'stac tuated in'" the operation of any of-saidde-' vices, for rendering the other devices in'op-I erable'bytheirassociated lines, means actue: ated at the completio-n'ofthegroupselecteing operation of said said other-I devices operable and thedeviceof the calling line group inoperable, and means actuated upon thevcompletion of the I indi-f vidual line selectingoperationof said switchswitch for rendering for rendering the "device of 1 the :calling ,line

group operable by itsassociated-lines. 1'

"6. The combination with a plurality of i 5 lines divided intogroupsyofaxplurality of finder switches for making'connection therewith,means for moving said finder switches, means controlled by anylineiintcalling for.

making oneof saidfinderiswitches operative. 1 i

to" connecttherewith, and meansadapted thereafter todeprive said callingline or 1 any. other line in the assoclated group' 'oficontrol over anyfinder switch, -1until' saidzvlinelisi found. V a;

In witness .whereof,--.I: hereunto subscribe: my name this 1916

